Knowledge of the state of an actual object during manufacture or even during operation is often partial. A manufacturer generally has at their disposal collections of measurements in folders of files (for example spreadsheets, photos or files of measurements) or in databases. It is then difficult, and in particular for large objects, not only to locate the data issued from actual measurements associated with a particular zone and to ascertain where the measurements were actually carried out, but above all to work out how they relate and correspond to each other or to a three-dimensional digital design model. Thus, ascertaining a state during manufacture or operation is not easy.
During installation, assembly and maintenance operations, an operator is required to carry out many tasks such as executing procedures, taking measurements, carrying out diagnostics, reporting on the work carried out, etc.
The operator generally uses paper plans or blueprints to ascertain and locate the various tasks to be carried out. He will also use conventional measuring means such as a measurement tape. This way of working may prove to be time-consuming, and errors may occur (positioning errors, damage, incorrect references, etc.).
One way of carrying out these tasks more rapidly and effectively is to project the information directly onto a surface of interest. The surface of interest corresponds to the surface with which the operator must interact.
It is for example possible to use a laser marking system such as that described in United States patent application US 2009/0195753 A1. This application discloses a device for the projection of laser markings onto the exterior of a vehicle, comprising a plurality of laser projectors, an image of the exterior of the vehicle projected in a synchronised form by said laser projectors, a computer connected to the laser projectors and a workstation connected to the laser projectors by way of the computer and allowing the images projected by the laser projectors to be coordinated. However, this information-projecting device is complex to implement and only allows a small amount of information to be displayed because of the inherent limitations of laser projection (Nicker, loss of brightness).
A rather similar device is described in European patent application No. EP 1 719 580 A2. Specifically, this patent application discloses a device for projecting information onto a surface of interest by way of laser projectors. This device uses metrological emitters allowing, by way of metrological receivers positioned on the surface of interest and on the laser projectors, the position and orientation of the latter to be ascertained. However, this device possesses the same limitations as the preceding system and is therefore limited in terms of the type of information that can be displayed. In addition, the system of calibration is time-consuming because of the need to position various metrological emitters and receivers.
Another known type of projection means employs a video projector and a single video camera. This system is difficult and time-consuming to implement because it requires markers to be positioned beforehand in precise positions on the surface of interest.
At the present time, every known information projecting solution is unfortunately either complex, inflexible and difficult to move, or time-consuming to calibrate. Therefore, these methods prove to be ineffective and unusable in most assembly operations. Furthermore, they are generally designed to carry out a single very specific task, such as the designation of a position or only the tracking of targets.
There is therefore, at the present time, a clear need to be able to carry out more simply and effectively, movable and flexible projection of information with a high degree of precision.